Octopus Deploy – The user name (UPN) could not be determined for principal

When you install Octopus Server, and you integrate with Active Directory for authentication, you may encounter an error stating that the UPN could not be determined for the account you’ve specified to be the Octopus Deploy Administrator.
In my case, I tried to use the default domain administrator account, which in our environment does not have its UPN configured.

Enable it on the account you’re using so that OctopusDeploy can use it: